Control system



July 26, 1938. w. R. TALIAFERRO CONTROL SYSTEM Filed April 24, 1935 3Sheets-Sheet l INVENTOR 6, 1938. w. R. TALIAFERRO 2,125,055

CONTROL SYSTEM Filed April 24, 1955 3 She ets-Sheet 2 M M 0 0 4M 4 M M M4 m 7 an 7 4 y l938w w. R. TALIAFERRO 2,125,055

CONTROL SYSTEM Filed April 24, 1935 3 Sheets-Sheet 3 WlTNESSES: INVENTCR'20 "other objects of my invention will be explained which is carried bya contact block 21 secured to Patented July 26, 1938 UNITED STATESBATENT QFFlCE CONTROL SYSTEM William R. Taliaferro, Pittsburgh, Pa.,assignor to Westinghouse Electric & Manufacturing Company, EastPittsburgh, Pa", a corporation of Pennsylvania Application April 24,1935, Serial No. 17,969 3 Claims. (01. 171-229) My invention relates,generally, to control syscopper or other non-magnetic material. The cupterns, and, more particularly, to systems for con- \I5 is concentricwith the magnet l0, and is cartrolling the operation of electric motors.ried by a short shaft l6 which is mounted in An object of my invention,generally stated, is bearings l1 and IS. The bearing I8 is sup- 5 toprovide a motor control system which shall be ported by a frame member2|, which is secured simple and eflicient in operation. and which may tothe frame member l3 by screws 22, and the .be economically manufacturedand installed. end bearing 11 is supported by a bracket 23, se-

A more specific object of my invention is to cured to the frame member2| by screws 24. A

provide a relay for controlling the operation of laminated steel ring25, which surrounds the 10 an electric motor which shall be responsiveto the magnet lo and the cup I5, is clamped between 10 speed of themotor. the frame members 13 and 2|, thereby prodiding Another object ofmy invention is to provide a magnetic circuit for the flux of the magnetIO. for remotely varying the setting of a speed-re- As will be readily.understood, eddy currents sponsive relay. I are produced in the cup 15and the rotation of A further object of my invention is to provide v themagnet l produces a magnetic drag or 15 a system for regulating thespeed of an electric torque on the cup, the torque being approximotor;mately proportional to the speed of rotation of A still further objectof my invention is to prethe ma t U- Ho e p rotation o vent hunting of aspeed regulating system. the cup is prevented by a contact arm 26,

fully hereinafter or' will be apparent to those the shaft IS. Thecontact arm 26 is disposed beskilled in the art. I tween fixed contactmembers 28 and 29, which For a fuller understanding of the nature andare mounted on the stationary frame members. objects of my invention,reference may be hadw A calibrating sp 3| is disposed to pp the 15 tothe following detailed description taken in torque on the cup 15,thereby biasing the con:g,

v conjunction-with the accompanying drawingsin tact arm 26 against theupper contact member which: L 28 when the rotating magnet is drivenbelow Figure 1 is a view, in elevation, of a speed-rea predetermine'dspeed. When the torque prosponsive relay constructed in accordance withduced by the magnet to on the cup is suflicient rm my invention; toovercome the force of the spring 3|, the con- Fig. 2 is a view, insection, of the relay shown tact arm 26 is actuated. into engagementwith .in Fig. 1; the contact member 29. Therefore, it will be Fig. 3 isanother view, in elevation, of the reseen that the device is responsiveto the speed lay illustrated in Figs. 1 and 2; of the apparatus drivingthe rotating magnet l0 r Fig. 4 is a view, partly in section and partlyin and that it may be utilized as a sp r l and elevation, of amodification of the relay shown in also s a speed regulator, as Will hemore fully Figs. 1, 2 and 3; I explained hereinafter.

Fig. 5 is a view, in section, taken along the line In the modificatieh0f the relay Shown in Figs, V-V of Fig. 4; and r 4 and 5, the laminatedring 25 is omitted and a 40 Figs. 6, 7 and 8 are diagrammatic views ofconp 35 ompo ed of ama n tic'm ri l. u h as trol systems embodying myinvention. a Steel, is utilized, thereby providing a path for theReferring 'now to the drawings and partieumagnetieflux produced by therotating magnet larly to Figs. 1, 2 and 3, the speed-responsive re- 10:A thin layer 35 of copper, or other nonlay shown therein is of themagnetic drag type magnetic material, 18 p d n the inside of andcomprises a' rotating magnet II) which is t e m of th D s the laminatedring 45 mounted on the end of a shaft H by means of 15 d D the Structures w in Figs: stud bolts l2.- The shaft l,l isrotatably supported 2 and3, are combined into 35 8 r. in a frame member H! by a sleeve bearing l4and e y Simplifying the. structure. 5 'the shaft may be either directlyconnected or The p 35 is carried yt shaft rotfltably geared to anelectric motor, locomotive axle or mounted in a supporting frame 31,which may be 50 other rotating apparatus, whose speed it is deboltedonto an end bracket 38 of an lectricmosired to regulate or utilize as ameans of contor by stud bolts 39. The magnet It! may be setrolling theoperation of other equipment. cured to the end of the motor shaft (notshown).

As shown, the magnet I0 is disposed insideof by stud bolts 40, themagnet shaft ll being dis- .a cup l5, which may be composed ofaluminum,- posed at the center of the motor shaft. In this 55 manner therelay may be rigidly secured to an electric motor, or other apparatushaving a rotating shaft, the relay magnet being "driven at the samespeed as the shaft of the motor.

As shown in Fig. 4, the contact members 4|, 42, 43 and 44 are carried bythe contact block 21, which is secured to the shaft N5 of the cup 35 andactuated thereby. The contact members 4|, 42, 43 and 44 are normallybiased by a compression spring 45 into engagement with contact members46, 41, 48 and 49, respectively, which are resiliently mounted on thestationary frame 31.

The spring 45 functions similarly to the spring 3| to oppose the torqueon the cup 35 and bias the contact members of the relay to predeterminedpositions. The spring may be calibrated by means of an adjusting screw5|, thereby varying the speed at which the rotating magnet I6 mustrevolve in order to produce suflicient torque dirt.

to'overcome the spring and operate the cup 35. A stop member 52 isprovided for limiting the travel of the cup 35. The, relay istotally'enclosed by a cover 53 for protection against moisture andFurther protection is aiiorded by a felt liner 54. 5

As illustrated in Fig. 6, the speed-responsive relay herein describedmay be utilized to open the circuit through the starting winding of asinglephase induction motor 66 when the motor has attained apredetermined speed. The motor 66 is provided with a starting winding 6|which may be connected across the power conductors 62 and 63 by means ofa starting switch 64 to start the motor. When the line switches 65 and66 are closed to connect the conductors 62 and 63 to any suitable sourceof alternating-current power, the actuating coil 61 of the startingswitch 64 is energized through a circuit established by contact members26 and 28 ofthe relay, which are biased to their closed position by thespring 3| on the speed-responsive relay.

As described hereinbefore, when the motor attains a predetermined speed,the torque developed by the relay is sumcient to overcome the force ofthe spring 3| and the contact members 26 and 2B are opened, therebydeenergizing the actuating coil 61 of the starting switch 64, whichpermits the switchto open and disconnect the starting winding 6| of themotor 60.

Centrifugally-operated switches have been utilarge motors. It isapparent that the speed-re sponsive relay herein disclosed may beutilized with a motor of any size, and that it may be built at acomparatively small cost. Furthermore, the speed setting of the relaymay be readily adjusted by means of the calibrating spring 3|, therebypermitting the relay to becalibrated to dee'nergize the starting windingat the'most-suitable speed for the particular motor being controlled bythe relay. 1

As shown in Fig. 7, the speed relay may also be utilized to control therelative values of resistance and reactance 'in a shunt 1| for theinterpole winding 12 of an alternating-current motor 13, of thecommutating type. In order that satisfactory commutation of the motor 13may be obtained at various operating speeds, it is necessary to vary therelative values of resistanceand reactance in the-interpole shunt 1|, asis fully described in Patent No. 1,922,724, issued August 15, 1933, toS. H. Cowin and L. J. Hibbard. The shunt 1| includes a reactor 14 andresistors 15 and 16, which are connected in series circuit relation withthe reactor 14. -As shown, an elec- 5 tlcally-operated switch 11 isprovided for short circuiting the reactor 14 when the switch 11 is inthe deenergized position. When the actuating coil 18 of the switch 11'is ener'gized,'the reactor 14 is connected in the shunt circuit, and theresistor is short circuited from the interpole shunt 1|, thereby varyingthe relative values of resistance and reactance in the shunt for theinterpole winding 12.

Assuming that the motor 13 is operating at a 15 relatively low speed,the contact members 26 and 29 of the speed relay are separated by thespring 3| and the actuating coil 18 of the switch 11 is deenergized.When the motor- "attains a predetermined speed, the contact members 26and 29 are closed by the torque producedby the rotating magnet of therelay, as herein described, and the actuating-coil." is connected acrossa battery 19, thereby energizing-the coil and actuating the switch 11 toitsuppermost position to change the 5 relative valuesof resistance andreactance in the interpole shunt 1|.

In order that the speed at which the relay operates may be remotelycontrolled a solenoid BI is provided on the relay to oppose the spring3|, 30 as shown in Fig. 7. It will be understood that when the solenoid-B| is energized, less torque will be required to overcome the force ofthe spring 3| and permit the contact members 26 .and 29 to close.Therefore, the-relay will function to operate the switch 11 at a lowerspeed of the motor 13 than when the solenoid 8| is deenergized. Thesolenoid 8| may be energized by closing a switch 82, which may belocated at ,any suitable point, thereby permitting the speed 40 settingof the relay to be remotely controlled.

'In the motor control system illustrated in Fig. 8, the relay hereindescribed is utilized as a speed regulating device for controlling theoperation of a shunt motor 85, which is provided withan armature winding86 and a shunt field winding 61. A'sis well known in the art, the speedof an 'electric motor may be controlled by varying the current in themotor field winding. The relay is driven by the motor shaft, in themanner hereinbefore described, and the contact members of the relay areso connected in the motor circuit that the current in the shunt fieldwinding 81 is decreased wheh the contact members 26 and 28 are closed bythe spring 3|,,thereby' causing the speed of the motor 85 to increase.Referring to Fig. 8, it .will be seen that a resistor 88 is connected inseries circuit relation with the field winding 81, and a resistor 89 isconnected parallel to the field winding 81 when thecontaot members 26and 28 of the relay are closed, which causes a minimum amount of currentto flow through the field winding 81..

When the motor 85 attains a speed which will producesufiicient torque inthe relay, in the manner hereinbefore described, to overcome the forceof the spring 3| and open the contact members 26 and 28 and close .thecontact members 26 and 29, the resistor 88 is shunted and resistor 69 isdisconnected from the shunt field circuit and the 70 tact members 26 and26 remain closed until opened by the spring 8|, which will decrease themotor field current and cause the motor speed to increase when the cycleof operation is again repeated. In this manner, the relay may beutilized as a speed regulator to control the speed of the motor 88.

In order to prevent hunting or surging of the regulating system, thesolenoid coil 8| may be connected either in series with or parallel tothe resistor 88,v as shown. Thus the coil 8| is energized when thecontact members 28 and 28 are closed by the spring 8|. The circuitthrough the coil 8| may be traced from the power conductor 8| throughthe resistor 88, conductor 92, contact members 28 and 28, conductors 84and 88, thecoil 8| and conductor 88 to the power conductor 92.

As the solenoid 8| opposes the spring 3| when energized, it will be seenthat the solenoid .8| tends to prevent overshooting oi'.'the regulator,since it will cause the contact members 28 and 28 to open slightlybefore the motor has attained the maximum speed normally permitted bythe regulator. Since the solenoid 8| isdeenergized when thecontactmembers 26 and 28 are opened by the torque produced in the relay as aresult of the increased speed of the motor, the spring 8| is enabled toagain close the contact members of the relay without having to overcomethe force of the solenoid 8|.

In this manner, the speed of the motor 88 is regulated by controllingthe current in the field winding 81 by means 0! the resistors 88 and 88,which are alternately connected in and disconnected from the fieldwinding circuit by means of the contact members on the speed regulatingrelay, and hunting of the regulating system is reduced by the action ofthe electrically energized solenoid 8|. 1

From the foregoing description, it is apparent that I have provided aspeed-repsonsive device regulator to control the speed or electricmotors which may be economically constructed and may be readily utilizedas a speed relay to control the operation for numerouselectrical ormechanical devices, and may also be utilized as a speed of varioustypes. Y I

I! desired, the relay may be modified to constitute a speed-responsivedevice having a time delay characteristic by permitting the cup member01 the relay to rotate and drive a gear train loaded with a spring orfriction load. In this manner contact members or mechanical trip devicesmay beoperated in sequential relation by the relay within apredetermined time after the cup starts to rotate, thereby providing atime element after a certain speed is reached.

While I have illustrated the manner in which the speed-responsive devicemay be connected to and utilized with various electrical devices, itwill be understood that it may be readily utilized in connection withmechanical apparatus, as well as electrical.

Since many modifications may be made in the apparatus and arrangement ofparts without departing from' the spirit of my invention, I do not wishto be limited other than by the scope of the appended claims.

I claim as my invention:

1. Ina motor control system, in combination,

an electric motor, a field winding for said motor,

a speed-responsive relay having a rotating member driven by said motor,a rotatablemember magnetically actuated by the rotating member, springmeans for governing the movement of the rotatable member to control thecurrent in the 1 motor field winding, thereby regulating the speed ofthe motor, and electro-magnetic means controlled by said rotatablemember to vary the effect of said spring means.

2. In a-motor control system, in combination,

.an' electric motor, a field winding for said motor,

a speed-responsive relay having a rotating member driven by said motor,a rotatable member magnetically actuated by therotating member,

' spring .means for biasing the rotatable member to shunt the motorfield, thereby regulating the speed of the motor, electro-magnetic meansdisposed to vary the eflect of said spring means, and means actuated bysaid rotatable memberfor controlling the energization of saidelectro-magnetic means.

3. In a motor control system, in combination, an electric motor, a fieldwinding for the motor, a speed-responsive relay} having a rotatingmember driven by said motor, a rotatable member magnetically actuated bythe rotating member to increase the'motor field current, spring meansfor biasing the rotatable member to decreasethe field current, therebyregulating the motor speed, electrically-energized means disposed, to,oppose the spring means to prevent hunting of the regulating system, andmeans actuated by said rotatable member for controlling the energizationof said electrically energised means.

WIILIAKR.

